In the past decade, disposable diapers have become increasingly popular. One of the recent developments in this area is the inclusion of elasticized leg openings in the diaper construction. The result of the utilization of elastic legged diapers has been to provide a diaper having a better appearing fit and better fit in some instances.
Such an elastic legged diaper is described in U.S. Pat. No. 3,860,003 (issued to Kenneth Barclay Buell). The integral disposable diaper described therein has the traditional components, a fluid-permeable facing sheet, a fluid-impervious backing sheet and an absorbent material sandwiched between the sheets and adhesively bonded to the backing sheet. The patent further discloses a side flap in the crotch area with the elastic means secured to the side flap in an elastically contractible condition to gather the side flap. The distance between the elastic edge and the absorbent material in the crotch area is at least 3/4" and it is indicated that absorbent material may be present in the side portion. As set forth therein, if fluff absorbent is included in the side flap it is designed to be extremely flexible, i.e. having a maximum Taber stiffness of six gm-cms and preferably less than three and most preferably less than 0.5. (Taber stiffness as used throughout this application refers to gm-cm units of measurement.)
An example of another disposable diaper with elastic legged portions is that disclosed in U.S. Pat. No. 4,050,462 (issued to Lin-Sun Woon and Dan D. Endres). This patent teaches the concept of providing increasing amounts of absorptive material in the crotch area by utilizing the elastic in relatively close proximity to the edge of the absorptive component with the elastic being attached to either the facing or backing sheet. In this patent, by placing the elastic within 1/2" of the absorbent material, gross transverse rugosities are formed which provide this extra absorbent amount of material in the crotch area. In both of these patents, extended elastic material is attached to the crotch area and, when the elastic is relaxed the elasticized leg area is formed.
While elastic legged diapers such as those represented by the above described patents have been gaining in popularity, recently, the performance of the diapers from the standpoint of waste containment in the leg areas has not been as good as might be expected. Some leakage at the leg is still possible and has been most often noticed on active children.
It has now been found that the placement of the elastic relative to the edge of the fluff and the presence or absence of side flaps are not the only features to be considered for maximum use of absorbent material and retention of waste products. It is the particular configuration of the diaper profile as interrelated to these features which enables the maximum degree of waste retention and comfort to be obtained in elastic legged disposable diapers.